1. Field of the Invention
The present invention relates to a liquid wiping apparatus suitably used for an iron manufacturing process line, particularly for a molten metal plating plant in a molten metal plating line using a metal, such as zinc.
2. Description of the Related Art
In general, in a molten metal plating line of this sort, a process in which a strip (a metallic ribbon) having been continuously subjected to a preliminary processing, such as annealing, and held at a high temperature is led via a sink roll installed in a molten plating bath (a molten metal pot) so that it is ascended, the amount of the molten metal to be plated (molten metal thickness, membranous metal thickness) onto the strip is controlled during the ascending process, and the strip is then cooled in a predetermined cooling pattern to normal temperature is employed.
In an example, as shown in FIG. 8, following to that a strip 100 is once drawn into a molten plating bath 101, the strip runs such that the running direction thereof is turned by means of a sink roll 102 installed in the molten plating bath 101 and the strip is further drawn in a vertical direction via support rolls 103 arranged in the bath, so that the excess portion of molten zinc having been attached onto the surfaces of the strip 100 is blown away during the running with gas ejected from a pair of wiping nozzles 104, which are arranged face to face over the molten plating bath 101, to thereby control the amount of the molten zinc to be plated to a predetermined amount (See, Japanese Patent Application Laid-open No. 7-180019 (FIG. 1)).
Note that, in FIG. 8 where reference symbol 105 represents a pair of range finders, an analyzer 106 determines the vibrating state and shape of the strip 100 on the basis of the measurements given by the range finders 105, and a processing computer 107 controls the distance between the strip 100 and the wiping nozzles 104 to such an extent that they approach each other up to a limit at which they can avoid the contact therewith on the basis of the determined vibration and shape.
In addition, as shown in FIG. 9, the strip 100 is subjected to processings, such as surface cleaning, in the preliminary processing furnace, led into the molten plating bath 101, and then drawn upward via a sink roll 102. At a position where the strip is drawn up from the molten plating bath, the running line of the strip 100 is curved in an arc state by a first static pressure pad 108 and a second static pressure pad 109. Under such a circumstance, the excess molten zinc having been attached onto the strip 100 is blown off with gas ejecting from gas ejecting nozzles (slit nozzles) 108a, 109a for controlling the amount to be attached onto the strip 100, which are installed respectively at the strip-inlet sides of the respective static pressure pads, so that the amount to be attached onto the strip is controlled to a predetermined amount to be plated.
Further, the strip 100 is adapted to be firmly held so as not to vibrate itself with static pressure caused by gas which is ejected from the plating coverage controlling gas ejecting nozzles 108a, 109a and gas ejecting nozzles (slit nozzles) 108b, 109b installed respectively at the outlet sides of the respective static pressure pads (See, Japanese Patent Application Laid-open No. 7-102354 (FIG. 1)).